One in four caregivers for ill or elderly relatives and friends said in a survey released on Tuesday that they suffer from depression, a figure far higher than for the U.S. population in general.

By comparison, 9 percent of all Americans are estimated to suffer from depression, according to a study released last year by the U.S. Centers for Disease Control and Prevention in Atlanta.

The California-based company Caring.com, a website for caregivers that commissioned the online survey of 400 respondents, said the high level of depression reported by those attending to a loved one comes as many face their own health issues.

The survey also found that a third of family caregivers spend more than 30 hours a week in that role, and 77 percent are concerned about the impact of their duties on their savings. Most of the caregivers were attending to an infirm parent, while the rest were caring for a spouse, relative or friend.